1. Field of the Invention
The invention relates generally to holders for storing and retaining hemostatic clips prior to use. More particularly, the invention relates to hemostatic clip cartridges which facilitate the storage and retention of a plurality of hemostatic clips within a corresponding plurality of individual chambers of the cartridge prior to withdrawal of the clips by a forceps-type clip applier.
2. Description of the Prior Art
Hemostatic clips have long been used to ligate or clamp blood vessels during surgical procedures. The clips are generally made of either a biocompatible metallic material or of a polymeric or non-metallic material The term "non-metallic" as used herein means anything other than metallic materials. In general, the clips are generally C-shaped, U-shaped or V-shaped and are designed such that the opposing legs of the open clip are able to be closed together by being compressed by the jaws of a forceps-type clip applier. In the case of metallic clips, the material is sufficiently strong such that the clips remain in their crimped, closed position merely by squeezing the legs together. In the case of plastic-type clips, the material is not as strong and requires some auxiliary latching mechanism to keep the clips closed. For the foregoing reasons, metallic clips are generally symmetrical while plastic clips are not. The latching mechanism generally comprises a hook-type arrangement molded with or otherwise secured to the plastic clip. One example of such a plastic ligating clip is shown in U.S. Pat. No. 4,834,096 (Oh et al.) assigned to the assignee hereof.
Because the clips are small and because many clips are usually used in a surgical procedure, holding devices are used to store and retain the clips--whether metallic or plastic--between the time of their manufacture and ultimate use in a surgical procedure. While numerous clip cartridges are known, they all serve to prevent the clips from becoming loosened during shipment and handling and from becoming completely dislodged. A distinction should be made between clip cartridges intended for use with "manual" clip appliers and those intended for use with "automatic" clip appliers. As used herein, the term "automatic" means those clip appliers which retain a plurality of hemostatic clips adjacent the jaws of a clip applier in a way such that a new clip is automatically fed to the jaws after the previous clip has been crimped into place. As used herein, the term "manual" means clip appliers which receive one clip at a time between the jaws and which have to be reloaded manually after the previous clip is crimped. The reloading operation is generally accomplished by inserting the jaws of the applier into a clip holder or cartridge which is generally provided with a plurality of longitudinally spaced, clip retaining chambers. A single clip is retained in each chamber by a variety of means and removed from its chamber by a forceps-type clip applier which is inserted as desired into each clip chamber and secured to the clip sufficiently to overcome whatever clip retention means is utilized to enable the clip to be removed from the clip chamber.
Various mechanisms are known by which clips may be retained within the chambers of clip cartridges. With respect to metallic clips, friction between the clip and the side walls of its individual chamber is generally sufficient to retain the clip. The clip cartridges are generally made of molded plastic material such that the walls of each clip chamber are somewhat resilient and able to be pushed away from each other when the clip applier jaws are inserted into the chamber to retrieve the clip. An example of a cartridge holding the clips in their respective clip chambers by means of frictional engagement with the side walls of each chamber is shown in U.S. Pat. No. 4,076,120 (Carroll et al.). In some prior art clip cartridges, each individual clip chamber is provided with a central post generally conforming to the shape of the open clip although being slightly larger so that when the clip is pushed onto the central post, frictional contact between the legs of the clip and the central post retains the clip within its chamber. Cartridges of this type are shown in U.S. Pat. Nos. 3,270,745, 3,326,216, 3,363,628, 3,439,522 and 3,439,523, all issued to E. C. Wood.
Prior art cartridges are also known which retain clips in a partially straightened state by maintaining each clip under tension within its chamber by the interaction between the central post in the chamber and the central part of the clip and protrusions extending into each chamber toward the central post (from the ends). The clip is retained by having its central hinge part pushed upwardly by the central post and its ends pushed downwardly by the protrusions. Such a cartridge is shown in U.S. Pat. No. 3,713,533 (Reimels) and U.S. Pat. No. 4,146,130 (Samuels et al.)
Another type of prior art cartridge is known which has a plurality of ribs extending from each side wall of each clip chamber inwardly toward the clip to retain the clip by frictional engagement with the ribs (U.S. Pat. No. 4,696,396, Samuels). The aforementioned U.S. Pat. No. 4,146,130 (Samuels et al.) shows an alternative embodiment for the situation where clips are intended to be loosely maintained in the cartridge without frictional engagement between it and the chamber, the clips in such an event being retained in each cartridge by a covering tape which may be easily severed by the applier as desired.
With respect to non-metallic clips, the prior art cartridges suitable for holding metallic clips are not necessarily suitable because the plastic clips inherently have a greater resiliency and non-symmetrical structure. For example, the aforementioned prior art cartridges which rely on the interaction between the clip and central post are not suitable for use with non-metallic clips because there is generally insufficient compression in non-metallic clips to cause them to grip the center post adequately. Likewise, frictional engagement with either the side and/or end walls of the chamber could possibly, over a long period of storage time, adversely affect performance of the clips. It would be preferable to retain non-metallic clips in a natural, relaxed state without any external stress applied to the clips until they are ready for use.
One known prior art method of holding plastic clips is shown in U.S. Pat. No. 4,294,355 (Jewusiak et al.) which discloses one or more resilient fingers associated with each clip chamber for holding each clip in a particular fixed orientation. The entire cartridge may or may not be covered by a thin film having a plurality of lines of weakness over each clip to identify the clip location for easy retrieval by the clip applier.
U.S. Pat. No. 4,361,229 (Mericle) discloses a cartridge for non-metallic clips wherein each clip is retained in its individual chamber by the interaction between a central post supporting each clip and paper flaps extending into each end of each chamber, the paper flaps being formed from a paper film interposed between a base portion of the cartridge (to which the central post is secured) and a top portion.
The known prior art cartridges suitable for non-metallic clips are relatively complex to manufacture and load and it is an object of this invention to produce a hemostatic clip holder of simplified structure and which also simplifies the loading of clips into the holder.
It is another object of this invention to provide a hemostatic clip holder for retaining clips during shipping and handling while enabling the withdrawal of the clips by clip appliers in preparation for use.
It is also an object of this invention to produce a unitary clip holder for storing and retaining a plurality of hemostatic clips for subsequent removal by an associated clip applier.
It is a further object of this invention to produce a hemostatic clip holder for storing and retaining a non-metallic hemostatic clip for subsequent removal by an associated clip applier.
It is a further object of this invention to produce a hemostatic clip cartridge for storing and retaining a plurality of non-metallic hemostatic clips in a natural, relaxed state prior to their subsequent removal by an associated clip applier.